Abstract

When sampling units selected from a population and measurements indicate presence or absence of a trait, it is possible to either classify every sampling unit as positive/negative or estimate the prevalence of the trait. The former is desired when the interest is in identifying all sampling units that test positive (and hence possess the trait). The latter is useful when the interest is not in the status of individual sampling units that possess the trait. The problem, then, is to estimate the sampling units in the population that possess the trait, when presence. Absence measurements are obtained on composite samples. Here, the values on the individual sampling units in the population are assumed to be independent and identically distributed random variables.